Petra Holden

African ecosystems remain underrepresented in the plant trait datasets used to parameterise land surface models (LSMs), limiting our confidence in simulations of African landscapes. We assessed whether African plant trait data can improve parameterisation of plant functional types (PFTs) in the Joint UK Land Environment Simulator (JULES vn 7.1) model by updating two key photosynthetic traits: leaf mass per area (LMA) and leaf nitrogen content (Nmass). First, we evaluated African-derived trait estimates relative to default JULES parameters. We then analysed impact of mean annual temperature, mean annual precipitation and an aridity index on variability in these traits using generalized additive mixed models (GAMM), and tested the effect of updated trait parameter values on simulated gross primary productivity (GPP) against data from 16 African eddy covariance sites spanning different biomes. Comparison with JULES default parameters showed that African trait values differed for several PFTs, highlighting the value of trait-informed regional parameterization for representing African vegetation more realistically. GAMM analysis showed that LMA and Nmass varied nonlinearly across climate space, indicating that African leaf trait variation is shaped by interacting environmental gradients rather than single climate drivers. Incorporating the revised trait values into JULES generally produced modest improvements in simulated GPP. Improvements were expressed primarily through reduced bias and root mean square error, with little effect on temporal correlation. Performance gains were most evident at grassland sites, highlighting the limitations of representing diverse vegetation using single PFT-level trait values. This study demonstrate that regionally derived plant trait data can refine LSM parameterisation and can improve aspects of model performance in African ecosystems. They also show that regionally derived trait data provide a practical basis for evaluating and updating default model parameters, while highlighting the need for approaches that better represent within-PFT trait variability across environmental gradients and biome types.

Nature-based solutions (NbS), including ecosystem-based adaptation, are increasingly proposed for climate action in African cities, but the evidence base is fragmented and lacks systematic synthesis of what is being implemented, where, and how effectively. We analysed 112 studies retained from a systematic review, covering 134 urban areas across 42 countries and including 45 informal settlements. Five NbS typology classes are inductively derived including: Green spaces; Rivers, catchments and drainage systems; Coastal systems; Green buildings; and Urban agriculture and multi-use gardens. Urban green spaces dominate the evidence (49% of studies) and are the most multi-functional class. Urban agriculture and multi-use gardens are under-recognised in headline framings, named as primary in only 5% of studies but appearing in 34% of the wider intervention mix. Evidence is increasing but concentrates geographically on larger cities. Successful climate change adaptation and mitigation outcomes are reported by 72% and 27% of studies, respectively. Heat mitigation is the most frequently quantified adaptation outcome, with temperature reductions up to 12.2 °C reported in proximity to urban green and blue spaces across the continent. Qualitative evidence links urban NbS to effective coastal protection, flood risk reduction, and increased water security. Multi-stakeholder governance anchored by local actors, and meaningful community participation are consistent enablers of effective implementation. However, insufficient long-term funding and livelihood disruptions and displacement raise concerns about long-term impacts. Priority research gaps include longitudinal effectiveness monitoring, financing mechanisms for informal contexts, systematic assessment of mechanisms behind inequitable outcomes, and evidence from under-represented regions and smaller cities.

Climate change generates harmful effects1,2. Across ecosystems, communities, infrastructure, and economies, among others, the consequences of rising temperatures, shifting precipitation, sea level rise and intensifying extremes are overwhelmingly adverse2. These harms include economic damages to crops, infrastructure, settlements and livelihoods, and non-economic losses to biodiversity, health, cultural heritage, territory, identity and social cohesion1,2. The dominant descriptor from Intergovernmental Panel on Climate Change (IPCC) assessments is “impacts,” which the IPCC Sixth Assessment Report (AR6) explicitly defines as consequences that “can be adverse or beneficial”3. In a literature documenting near-universal harm, the systematic use of an unqualified neutral default is imprecise, analytically misleading, and potentially politically consequential. This neutral framing of documented harm obscures what the evidence shows and erodes the accountability the evidence demands. The problem is compounded by routine conflation of the UNFCCC political process of “Loss and Damage” (capitalised) with the empirical phenomenon of “losses and damages” (lowercase). Drawing on a systematic analysis of all seven reports from the IPCC's 6th assessment cycle, we show that terminological fragmentation is pervasive, consequential, and correctable. In the current environment, in which climate science is increasingly shaped by misinformation and disinformation and sustained political attack, such imprecision increases the scope for distortion and severe misinterpretation. Across the IPCC's 7th assessment cycle reports there is opportunity for clarity, but the implications extend well beyond the IPCC. We argue that the climate assessment community should adopt three terminological propositions that close the gap between the scientific evidence base and the more general language used to summarise it: (1) losses and damages as the default descriptor for observed and projected adverse outcomes where evidence documents adverse outcomes; (2) beneficial impacts for outcomes demonstrably positive at the system scale; and (3) impact retained as the umbrella term, reserved unqualified for genuinely ambiguous cases

Land surface models are fundamental for simulating coupled carbon, water and energy exchanges in Earth system models, yet their performance remains poorly constrained across Africa's diverse hydroclimatic gradients. We evaluate the Joint UK Land Environment Simulator (JULES) using eddy covariance observations from 16 flux towers spanning major African ecosystem types. Model skill is assessed for gross primary productivity (GPP), ecosystem respiration (Reco), and evapotranspiration, and we examine how model bias and error vary along gradients of mean annual temperature, aridity index, and precipitation anomalies. JULES reproduced broad seasonal dynamics of carbon and water fluxes across several ecosystems but showed systematic limitations in simulating Reco and interannual variability of GPP. Model performance differed among ecosystem types, with wetlands exhibiting large model‐observation mismatches and cropland sites showing GPP overestimation linked to excessive simulated leaf area index. To isolate environmental controls on performance, we applied linear mixed‐effects modeling to partition site‐level variability from climate‐driven effects. Aridity and precipitation anomalies emerged as dominant predictors of model bias and error, with wetter and anomalously humid conditions associated with larger deviations from observations, indicating limitations in representing soil hydrology and vegetation water stress processes. By integrating an expanded African flux tower network, this study provides a comprehensive regional evaluation of JULES. The results identify hydroclimatic regimes where model development should be prioritized and emphasize the importance of strengthening benchmarking across underrepresented African ecosystems to improve model transferability and support reliable climate and land management decision support under environmental change.

As global funds are increasingly directed towards nature-based solutions (NbS), these interventions are expected to support climate-resilient development, particularly in Africa. Yet there are concerns that NbS can create new social inequities or exacerbate existing ones. We systematically reviewed 93 English-language studies of NbS implemented in southern Africa, published between 1960 and 2021, to identify the underlying drivers of negative social impacts and unequal benefit sharing. Our findings show that inequitable outcomes often persist despite equitable intentions, with the greatest burdens falling on poorer and marginalised groups. We inductively mapped the reasons for these inequitable outcomes into 32 Social Equity Constraints (SEC), which are factors that hinder the achievement of procedural, distributional, and recognitional equity. By identifying the contextual factors through which social equity in NbS is constrained or enabled, this study provides a framework to help funders, implementers, and communities design more equitable and sustainable NbS.

Co-production is essential for usable and useful climate services, yet expert-driven, supply-side approaches and limited engagement persist. We investigate the relationship between users’ current climate-service use and desired needs for completely new climate services for nature-based solutions in Sub-Saharan Africa, based on 530 interviews. We found a 39–53% overlap between current use and desired need priorities (Cohen’s Kappa 0.4–0.5, p < 0.0001). Stakeholder type did not predict use–need overlap (rate ratios 0.95–0.99, p > 0.08), though location did (0.88–1.27). Nearly all respondents (96%) reported using or needing climate services, but these services require strengthening through integration of knowledge systems and improvements in accessibility, timeliness, skills, trust, and climate-change literacy. Gaps between current use and desired needs point to priorities for new climate services, including integrated climate-risk information and community and digital sharing channels. Simply asking users what they need may blur the distinction between strengthening existing services and identifying genuinely new needs.

As global funds are increasingly directed towards nature-based solutions (NbS), these interventions are expected to support climate-resilient development, particularly in Africa. Yet there are concerns that NbS can create new social inequities or exacerbate existing ones. We systematically reviewed 93 English-language studies of NbS implemented in southern Africa that reported inequitable outcomes, including negative social impacts and unequal benefit sharing. Our findings show that inequitable outcomes often persist despite equitable intentions, with the greatest burdens falling on poorer and marginalised groups. We inductively mapped the reported reasons for inequitable outcomes into 32 Social Equity Constraints (SEC). This set of constraints provides an empirical account of contextual equity by identifying factors that hinder procedural, distributional, and recognitional equity. The resulting SEC framework can help researchers, funders, implementers, and communities identify and address the constraints through which NbS can produce inequitable outcomes, supporting more equitable and sustainable NbS design.